1. Field of the Invention
The invention relates to a voice communication system for carrying out communication via a VoIP (Voice over Internet Protocol) system and its method.
2. Description of the Related Art
As disclosed in, for instance, “Denwaya ga Kaita IP no Hon (A Book on IP Written by a Telephone Mechanic), by Yoshikazu Kobayashi, RIC TELECOM Ltd., Mar. 20, 2002, ISBN4-89797-714-2 (Reference 1), pp. 312-347” and elsewhere, a system known as VoIP (Voice over Internet Protocol), by which voice communication is carried out by transmitting voice data encapsulated in an IP packet in a network, has been proposed in a recent year.
In this VoIP system, multicast calls that are initiated at a single terminal and addressed to many terminals at the same time are possibly carried out, as well as the one-to-one calls used for customary telephone communication.
Also, various telephone response systems are disclosed in, for instance, Japanese unexamined patent publications 2001-333177, 2001-136272, 2000-324229, 2001-216875, 2001-059499 and 2002-077437 (References 2 through 7).
However, none of these discloses a voice communication system that makes use of the multicast call feature of VoIP.